Russian emigre and former cabdriver made first fortune bartering fertilizer and oil with Soviets in 1980s. Reinvested in real estate. Today owns 7 office buildings in Manhattan; 1-million-square-foot office tower in downtown undergoing extensive renovations. New Trump Soho condo hotel development recently announced. Son, Alex, became president of the Sapir Organization in 2006; dad remains chairman, checks in often from his penthouse overlooking Acapulco Bay in Mexico or his Versace-accented yacht. Plans to house vast ivory collection in famed Duke-Seamans Mansion this year.